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Re: HTTP/2 Priorities Proposal

From: Amos Jeffries <squid3@treenet.co.nz>
Date: Thu, 10 Apr 2014 16:33:04 +1200
Message-ID: <53461F00.5050308@treenet.co.nz>
To: ietf-http-wg@w3.org
On 10/04/2014 3:21 p.m., Tatsuhiro Tsujikawa wrote:
> 2014/04/10 0:05 "Jeff Pinner":
>>>
>>> To change all weights, we have to issue PRIORITY frames for each root.
>>>
>>
>> Yes, changing the weight of a stream would require issuing a PRIORITY
> frame for each stream. With this proposal you cannot do it by changing the
> weight of the group.
>>
>> I believe that this is an acceptable tradeoff.
>>
>> Let me give a similar example where we reached the same conclusion:
>>
>> At one point we considered whether or not RST_STREAM should have an
> ASSOCIATED flag. The argument was that the server could send PUSH_PROMISE
> frames for some stream that the client did not want to receive pushes for.
> With the flag, the client could reset all of those streams with a single
> frame. We decided it was perfectly acceptable to send one frame for each
> stream and dropped the flag.
>>
>> With this change, to change the weight of multiple streams, you must
> issue one frame per stream, but IMHO this is worth it given the reduced
> complexity of the change, and more importantly, the ability that this
> change introduces of being able to completely proxy the priority
> information.
>>
>>
> 
> Proxy friendliness is a strong point for this proposal.

Indeed. Squid would very likely not have implemented PRIORITY beyond the
forced behaviour of dropping it on the floor. Simply being able to relay
values and let the endpoints sort the stream management out makes it a
lot more useful to everybody as a protocol feature.

Amos
Received on Thursday, 10 April 2014 04:33:29 UTC

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